The present invention in a preferred embodiment utilizes novel compositions to be applied to a wearer's skin to protect the skin from external heat fluxes applied naturally or artificially. These compositions comprise reflecting pigments and hydrogels for simultaneously reflecting heat away from the skin and diverting thermal energy to a complementary evaporative cooling mechanism. Further, methods of making the compositions and methods of use are also disclosed.
Current technologies exist that provide skin and face paint having camouflage and/or thermal reflective characteristics. For example, U.S. Pat. No. 5,254,406 discloses a face paint material for application to the skin of the human body. The face paint comprises metallic particles embedded in a gel, such as petroleum jelly. This invention is directed to the avoidance of detection of a soldier's face by thermal imaging devices, but would not protect against the burning of skin by intense thermal flux because its metal particles would typically conduct heat to the surface of the skin and gels like petroleum jelly would be ignited by such a thermal flux, therefore exacerbating heat injury and burns.
U.S. patent application 20090081453 discloses a low emissive camouflage paint comprising metal flakes having thermal reflective properties. The metal flakes are coated in a colored coating that is transparent in the thermal radiation range. It is notable that in this disclosure the colored moiety is transparent in the thermal radiation range. Moreover, the application is directed to a skin paint that provides thermal camouflage by reflecting the human body's infrared signal back to the skin instead of outwards to an infrared detection device. The metal powders are thermally conducting and would be expected to conduct the heat of an external intense flux directly to the skin of the wearer. Such skin paints would be unlikely to protect the skin from damage caused by intense thermal fluxes.
Infrared reflective pigments are also disclosed in U.S. Pat. Nos. 6,174,360; 6,454,848; and 6,989,056. These disclosed pigments reflect heat in the near infrared region, typified by 0.001 to 3 microns. Such pigments are available commercially under the trade names Cool Colors™ and Eclipse™ IR Heat and Energy Saving Pigments from Ferro Corporation and Arctic infrared reflecting pigments from Shepherd Color Corporation. U.S. Pat. No. 5,811,180 discloses heat reflective pigments that mitigate or prevent ignition of combustible substances by near-infrared radiation. This patent does not teach one skilled in the art of camouflage ‘make-up’ or how to make or apply compositions to living skin for the purpose of meeting the much higher challenge of preventing a burn injury when the skin is exposed to a ballistic heat flux. U.S. Pat. Nos. 7,241,500 and 7,452,598 disclose shingles comprising infrared reflective pigments that mitigate the absorption of solar heat and have resistance to thermal stresses. These patents do not disclose use of thermally-reflective pigments in skin paints.
The use of hydrogels to prevent or extinguish fire is well-known. For example, U.S. patent application 20060157668 discloses fire-fighting compositions comprising a water-insoluble superabsorbent polymer, a colorant and an opacifier. Protection of structures from the effect of an explosion by covering all or part of the structure with a water gel is described in U.S. patent application 20080229969. The prevention of combustion by the application of a reversible or degradable superabsorbent polymer and water is disclosed in U.S. patent application 20070001156. Fire retardant compositions comprising the potassium salts of carboxylate polymers are disclosed in U.S. patent application 20070262290. Fire retarding and/or extinguishing compositions based on at least one water absorbing polymer are described in U.S. patent application 20070289752. U.S. patent application 20030159836 describes thermosensitive hydrogels that have low viscosity at ambient temperature that can gel or solidify at high temperature to act as fire extinguishers.
Based on the prior art, there exists a need for novel topically-applied paint compositions and methods that efficiently protect skin from external thermal fluxes, conform to skin chemistry, and are easy to apply and/or to remove. The present invention provides such compositions and methods.